Synthesis and mechanochemical properties of biobased <scp>ABCBA</scp>‐type pentablock copolymers comprising poly‐<scp>d</scp>‐lactide (A), poly‐<scp>l</scp>‐lactide (B) and poly(1,2‐propylene succinate) (C)

Nishiwaki, Yasumasa; Masutani, Kazunari; Kimura, Yoshiharu; Lee, Chan‐Woo

doi:10.1002/pol.20210883

Cited by 8 publications

(7 citation statements)

References 35 publications

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“…The mechanical properties of linear ABA TPEs can be modestly tuned through the chemical composition and molecular weight, which defines the nanostructure, but adjusting the properties through these parameters tends to include trade-offs with processability and performance. The performance of linear TPEs can be enhanced with multiblock copolymers with polymer block sequences (AB) n A, ABC, − and ABCBA, − where the domain connectivity through bridging chains helps to improve the material toughness. There is a drawback in that each added block adds costs; this factor has limited the commercial adoption of multiblock copolymers, except for some high-value applications …”

Section: Introductionmentioning

confidence: 99%

Revealing Deformation Mechanisms in Polymer-Grafted Thermoplastic Elastomers via In Situ Small-Angle X-ray Scattering

Torres,

Furton,

Sevening

et al. 2023

ACS Appl. Mater. Interfaces

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The tunable properties of thermoplastic elastomers (TPEs), through polymer chemistry manipulations, enable these technologically critical materials to be employed in a broad range of applications. The need to “dial-in” the mechanical properties and responses of TPEs generally requires the design and synthesis of new macromolecules. In these designs, TPEs with nonlinear macromolecular architectures outperform the mechanical properties of their linear copolymer counterparts, but the differences in the deformation mechanism providing enhanced performance are unknown. Here, in situ small-angle X-ray scattering (SAXS) measurements during uniaxial extension reveal distinct deformation mechanisms between a commercially available linear poly(styrene)–poly(butadiene)–poly(styrene) (SBS) triblock copolymer and the grafted SBS version containing grafted poly(styrene) (PS) chains from the poly(butadiene) (PBD) midblock. The neat SBS (φSBS = 100%) sample deforms congruently with the macroscopic dimensions, with the domain spacing between spheres increasing and decreasing along and transverse to the stretch direction, respectively. At high extensions, end segment pullout from the PS-rich domains is detected, which is indicated by a disordering of SBS. Conversely, the PS-grafted SBS that is 30 vol % SBS and 70% styrene (φSBS = 30%) exhibits a lamellar morphology, and in situ SAXS measurements reveal an unexpected deformation mechanism. During deformation, there are two simultaneous processes: significant lamellar domain rearrangement to preferentially orient the lamellae planes parallel to the stretch direction and crazing. The samples whiten at high strains as expected for crazing, which corresponds with the emergence of features in the 2D SAXS pattern during stretching consistent with fibril-like structures that bridge the voids in crazes. The significant domain rearrangement in the grafted copolymers is attributed to the new junctions formed across multiple PS domains by the grafting of a single chain. The in situ SAXS measurements provide insights into the enhanced mechanical properties of grafted copolymers that arise through improved physical cross-linking that leads to nanostructure domain reorientation for self-reinforcement and craze formation where fibrils help to strengthen the polymer.

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Section: Introductionmentioning

confidence: 99%

Revealing Deformation Mechanisms in Polymer-Grafted Thermoplastic Elastomers via In Situ Small-Angle X-ray Scattering

Torres,

Furton,

Sevening

et al. 2023

ACS Appl. Mater. Interfaces

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“…Linear pentablock terpolymers, denoted as ABCBA, comprising five distinct blocks, represent a fundamental model for investigating the self-assembly of multiblock copolymers [6]. Both experimental studies [7][8][9][10][11] and computational simulations [12,13] have been employed to explore the phase behavior of these terpolymers in bulk. Various structures have been identified, including the lamellar phase structure (LAM3), the double gyroid (Q230) network structure, and the hexagonal perforated lamellae (HPL) structure.…”

Section: Introductionmentioning

confidence: 99%

Effect of Film Thickness on the Self-Assembly of CBABC Symmetric Pentablock Terpolymer Melts under 1D Confinement: A Dissipative Particle Dynamic Study

Guo

2023

Materials

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The study investigates the impact of film thickness on the phase behavior of pentablock terpolymers, denoted as C3B3A6B3C3, when subjected to wall confinement by utilizing the dissipative particle dynamics method. Phase diagrams were constructed to elucidate how factors such as block–block interaction strength, film thickness, and wall properties affect the self-assembly structures. In cases where the wall exhibits no preference for any of the blocks, lamellae phases with orientations perpendicular to the wall are observed. The order–disorder transition (ODT) temperature is found to be influenced by the interaction between the polymer and the wall in thin confinement scenarios. When the wall displays a preference for specific blocks, the orientation of lamellae structures undergoes variations. Lamellae tend to align parallel to the wall when the wall favors A or C blocks, and they orient perpendicularly when B blocks are favored. Furthermore, the mechanical properties of the lamellae structures are related to the conformations of the polymer chains. Structures where chains predominantly adopt a loop conformation exhibit enhanced elastic properties. The ratio of looping to bridging conformations can be adjusted by altering the film thickness and wall selectivity.

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“…However, it results in residual tin contaminants, limiting some applications of products. 6,7 Organocatalysts or the metal catalysts based on nontoxic Na and K have received much attention in the field of ROP. 6,[8][9][10][11][12][13][14][15][16][17][18][19][20] Recently, Waymouth et al developed (thio)urea anions for Brønsted acid-base synergistic catalytic ROP of cyclic esters.…”

Section: Introductionmentioning

confidence: 99%

“…Tin catalysts have been widely used in the industrial ROP processes. However, it results in residual tin contaminants, limiting some applications of products 6,7 . Organocatalysts or the metal catalysts based on nontoxic Na and K have received much attention in the field of ROP 6,8–20 .…”

Section: Introductionmentioning

confidence: 99%

Photoresponsive thiourea and urea catalysts for ring‐opening polymerization of L‐lactide

Cai

Zheng

Pang

et al. 2022

Journal of Polymer Science

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Stimulus responsive catalysts have received increasing attention. Photoresponsive catalytic polymerization is particularly attractive because the noninvasive and versatile nature of light. Most photoresponsive ROP catalytic systems exhibit low activities, allowing ROP to be completed within several hours to 10 h. In this contribution, a series of (thio)ureas bearing dithienylcyclopentene optical molecular switch moiety are designed, synthesized, and characterized.The photoresponsive effects in (thio)urea/alkoxide mediated ROP of L-lactide are investigated. These catalysts allow the ROP reactions of L-lactide to be completed within a few minutes to 1 h and the resulting polyesters have narrow molecular weight distributions. The dithienylcyclopentene moiety allows photoisomerization to be completed within 1 min. The catalytic activity of the ROP catalyst can be altered by the photoisomerization of the dithienyl cyclopentene moiety by exposure to ultraviolet or visible light, respectively.

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Synthesis and mechanochemical properties of biobased ABCBA‐type pentablock copolymers comprising poly‐d‐lactide (A), poly‐l‐lactide (B) and poly(1,2‐propylene succinate) (C)

Cited by 8 publications

References 35 publications

Revealing Deformation Mechanisms in Polymer-Grafted Thermoplastic Elastomers via In Situ Small-Angle X-ray Scattering

Revealing Deformation Mechanisms in Polymer-Grafted Thermoplastic Elastomers via In Situ Small-Angle X-ray Scattering

Effect of Film Thickness on the Self-Assembly of CBABC Symmetric Pentablock Terpolymer Melts under 1D Confinement: A Dissipative Particle Dynamic Study

Photoresponsive thiourea and urea catalysts for ring‐opening polymerization of L‐lactide

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